Random Variables Test Review

Is this binomial experiment? Shuffle a deck of 52 cards. Turn over the top card. Do not replace the card. Repeat the process 5 times. Let X = the card you observe.

• Yes

• No, the trials are not independent.

• No, there are more than 2 outcomes

Is this binomial experiment? Shuffle a deck of 52 cards. Turn over the top card. Put the card back in the deck, shuffle again. Repeat the process 50 times. Let X = the number of aces you observe.

• Yes

• No, the trials are not independent.

• No, there are more than 2 outcomes

Which one of these variables is a binomial random variable?

• Time it takes a randomly selected student to complete a multiple choice exam

• Number of textbooks a randomly selected student bought this term 

• Number of women taller than 68 inches in a random sample of 5 women

• Number of CDs a randomly selected person owns

An algebra 2 test has 6 multiple choice questions with four choices with one correct answer each. If we just randomly guess on each of the 6 questions, what is the probability that you get exactly 3 questions correct? (You need to figure out the p value first. It is not given to you.)

• 0.962

• 0.132

• 0.831

• 0.250

Tags

CCSS.HSS.CP.A.2

CCSS.HSS.CP.B.8

CCSS.HSS.CP.B.9

Bob is taking a 100 question test.  They have a 90 % probability of getting any one question correct.  WHICH IS THE CORRECT FORMULA TO FIND OUT THE PROBABILITY that they will answer EXACTLY 70  questions correctly?

• ₁₀₀C₇₀   ( 0.18  )³⁰ ( 0.90  )⁷⁰
  

• ₁₀₀C₇₀   ( 0.10  )³⁰ ( 0.90  )⁶⁰

• ₁₀₀C₇₀   ( 0.10  )³⁰ ( 0.90  )⁷⁰

• ₉₉C₇₀   ( 0.10  )³⁰ ( 0.90  )⁷⁰

Tags

CCSS.HSS.CP.B.9

A test has 8 multiple choice questions with four choices with one correct answer each. If we just randomly guess on each of the 8 questions, what is the probability that you get at least 3 questions correct?

• 0.886

• 0.332

• 0.678

• 0.208

Tags

CCSS.HSS.CP.B.7

CCSS.HSS.CP.B.9

A set of 20 cards consists of 10 purple cards and 10 green cards.  If you turn cards over one at a time after shuffling them and wait until you get your first purple, what distribution is it

• binomial, n= 20 and p= .5

• geometric p= .5

• none- same probability isn't happening each time

• normal distribution

A set of 20 cards consists of 10 purple cards and 10 green cards.  If you randomly pick a card after shuffling them and replace the card each time and wait until you get your first purple, what distribution is it

• binomial n = 20 and p=.5

• geometric p = .5

• neither

• normal distribution

Which of the following is true about geometric distributions?

• Geometric distributions are approximately skewed right.

• Geometric distributions are approximately symmetric.

• Geometric distributions are approximately skewed left.

• The shape could be symmetric or skewed.

Which of the following is false about binomial probabilities?

• Their distributions are approximately symmetric.

• Trials must be fixed.

• Events musts be independent.

• The probability of success must be 0.50